[Evaluation of EC-IC bypass flow by MR angiography using the presaturation technique]

MR angiography studies using the presaturation technique were performed in 7 patients who had received extra-intracranial (EC-IC) bypass surgery. With presaturation on the bypass vessels, disappearance of intracranial vascular signals suggests bypass effect. In our studies, good bypass effect was shown in 3 cases and poor effect in 2 cases, which correlates well to concurrent angiography. In two cases, bypass effect was shown only in a few cortical branches of MCA, but angiography confirmed recanalization of occluded internal carotid artery in one case, and growth of large network of transdural anastomoses in the other.